Ultraviolet (UV) curing has many applications in printing, coating and sterilization. UV-sensitive materials generally rely upon a particular amount of energy in the form of UV light to initiate and sustain the curing process (polymerization) within the materials. UV light fixtures provide the UV light to the materials for curing.
Using arrays of light emitting diodes (LEDs) in UV curing has several advantages over using arc lamps, including lower power consumption, lower cost, cooler operating temperatures, etc. Generally, the arrays consist of individual LED elements arranged in an X-Y grid on a substrate. Lenses may be molded over the arrays, such that a lens corresponds to each LED element and is centered over the element. The lenses may be raised or lowered on the Z-axis for focus. This type of fixture produces a reliable source of UV light having a highly-efficient, steady, uniform irradiance output.
However, UV curing processes generally have a non-linear polymerization rate that relates directly to the amount of energy supplied to initiate and sustain the reaction. These processes would benefit greatly from a higher peak irradiance.